Leading-in conductor



J. H. ANDERSON.

LEADING-IN CONDUCTOR.

APPLICATION FILED AUG-28,1915.

1 ,33 1,085. Patented Feb. 17, 1920.

INS/ENTER :J'UHN h: Azvrz'za 501v,

Hrs Arraazvsr.

UNITED STATES PATENT OFFICE,

JOHN H. ANDERSON, OF CLEVELAND, OHIO, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

LEADING-IN CONDUCTOR.

Specification of Letters Patent.

Patented Feb. 17, 1920.

Application filed August 28, 1915. Serial No. 47,798.

' To ail whom it may concern:

Be it known that I, JOHN H. ANDERSON, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga, State of Ohio, have invented certain new and useful Improvements in Leading-In Conductors, of which the following is a specification.

My invention relates to leading-in conductors which are sealed in electric incandescent lani and other similar devices which comprise a container of glass or other vitreous material through which the conductor extends and with which it must form a gas tight seal.

The object of my invention is to permit the use, as leading-in conductors, of metals having a materially difierent co-efiicient of expansion from that of the glass or other vitreous material into which such conductors are sealed.

According to the present invention, leading-in conductors may be used whose coefficients of expansion difl'er considerably from that of the glass into which they are sealed, This is accomplished by so shaping the sealed-in portion of the leading-in conductor that any space which might ordinarily be formed between the conductor and the surrounding glass due to difference in expansion will be effectively blocked. The present invention may be applied also to leading-in conductors which are in use at present to improve the efficiency thereof. However, the invention has to do more particularly with leading-in conductors of the character hereinbefore referred to composed of metals whose coeificients of expansion are greater than that of the glass and which are desirable. for use as leading-in conductors on account of their high conductivity, ease of working, comparatively low cost and other properties.

My invention is especially adapted for use in connection with leading-in conductors composed of metals which will be wet by the surrounding vitreous material or with I connection with cop er, cobalt and other metals and alloys wl ibse coeflicients of expansion are such that they do not form good seals without the application of the said invention and whose other properties make them particularly desirable as leading-in wires. My invention particularly relates to leading-in conductors which are of the same composition throughout.

One feature of my invention consists in forming upon that portion of the conductor which is to be sealed into the glass a channel or series of channels which extend circumferentially, that is, around the conduct-or. The said channels are so located that they will be completely embedded in the glass. During the sealing-in operation the glass will be compressed into the said channels. The channels are of such depth that the subsequent cooling of the seal will I not cause the withdrawal of the glass from the said channels. This will tend to block any alr passage which might otherwise be formed between the conductor and the surrounding glass. Moreover, as the preferred form of-my invention contemplates the use of copper, cobalt or other metal which possesses an aliinity for glass or which is capable of being wet by the glass, there will be a tendency for the glass to adhere to the sides of the channels, and this also will tend to preserve the seal. Particularly is this the case Where the channels are divided by thin cir cumferential projections which are capable of being stretched to a certain extent and thus accommodating themselves to the strains existing in the seal during the cooling of the .same. I prefer to use a series of channels so that there will be a number of dams or baffles in what would be the normal air passage; although it will be apparent that a single channel in a conductor whose expansion is substantially greater than that of glass would be within .the scope of my invention. It will also be apparent that a single circumferential projection whose width is slight compared with that of the conductor would be within the scope of my invention provided the material of the conductor is such that it is wet by the glass.

It will be obvious that there are a number of methods of forming the channels in the leading-in conductors which will be apparent to those skilled in the art. It is preferable, in order to obtain clean out channels, that a cutting method be employed embodying my invention, but it is to be understood that these are merely illustrative and that many modifications may be made which will come within the scope of my invention.

In the drawing, Figure 1 is an elevation of an incandescent lamp which serves as an illustration of a device to which my invention may be applied. Fig. 2 is an enlarged vertical section of one end of the hollow stem through which the leading-in wires extend and which contains the seal. .Fig. 3 IS a vertical section on a still larger scale of the sealed in portion of one of the conductors shown in Fig. 2.

In the drawing, 10 is a bulb of an incandescent lamp having a base 11 to which are connected the leading-in wires 12-13, which extend through the hollow glass stem 14 and are sealed therein at the end 15. The said leading-in wires are connected in the ordinary manner to a filament 16 mounted on suitable supports 17 held by the central glass rod 18. The portions 19 and 20 of the leading-in wires 1213 are sealed into the end of the stem 14 and it is to these portions that my invention relates. As shown, the leading-in wires 1213 are continuous, extending from the base 11 to the filament 16. I prefer that these leading-in wires be of copper, cobalt or of other metal which possesses high conductivity and other properties which make it desirable for use in this connection. In certain cases it may be desirable to have the portions 19 and 20 of the said leading-in wires com osed of a different metal than the rest of t e wire, in which case these portions may be united to the wire as is done in the case of latinum and certain platinum substitutes. t is preferable, however, to use a continuous wire of the same composition throughout on account of greater economy of production.

The sealed in portion of the leading-in wire, as shown in the drawing, and particularly in Fig. 3, is covered with a number of channels 21. It is preferred that the leading-inwire. 12 in Fig. 3 be of the size ordinarily used at present in incandescent lamps which is 16 mils in diameter for ordinary wattages. However, larger or smaller wires may be used. The number and size of the channels which it is desirable to form in the wire is amatter for test in order to obtain the best results, but good results have been obtained with 16 mil wire having 6 channels in a distance of 3 millimeters, the channels bein slightly wider than the projections there etween and the depth being about one-fourth that of the wire diameter. The best results are secured where the circumferential projections between the channels are very thin in comparison with the said channels. For example, the said projections may be onefourth the width of the channels. The deeper the channels, the better, but there will be a limit set by the strength of the material and the difficulties of manufacture. The channels shown in Figs. 2 and 3 are annular and do not communicate one with the other. This is the preferred form. The said channels are also substantially rectangular and this is also believed to be preferable. Flanges or projections 22 between successive channels should be quite narrow since this probably allows a certain stretchllilhg of the flange and serves to increase the e ciency of the seal. It is obvious, however, that all of these are matters which are capable of ready determination and standardization.

Good results may be obtained by treating the leading-in wire or at least the portion containing the channels by the borating method hereinbefore referred to. However, care had better be taken not to fill up the channels and to this end the coating should be quite thin.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. The combination of a vitreous container and a leading-in conductor sealed directly into the material thereof, said conductor being composed of a homogeneous metal having a substantially higher co-efli-' cient of expansion than said vitreous material and having one or more thin radially extending flanges located at the sealed-in portion thereof.

2. The combination of a vitreous container and a homogeneous copper leading-in conductor sealed directly into the vitreous material and having one or more thin radially extending flanges located at the sealedin portion thereof.

3. The combination of a vitreous container and a homogeneous copper conductor sealed directly into the vitreous material thereof, said conductor bein provided at the sealed-in portion thereof with one or more thin radially extending flanges having thereon a thin coating of material which will flux with said vitreous material.

In witness whereof, I have hereunto set my hand this 26th day of August, 1915.

' JOHN H. ANDERSON. 

